The aim of these studies is to characterize the membrane mechanisms of the individual cell types in the retina, and relate membrane events to visual function. To this end we have utilized a newly-developed retinal preparation - the living retinal section. Retinas of tiger salamanders are used because the cells are large, easy to maintain and to penetrate with intracellular microelectrodes - under visual control in this preparation. Work in progress includes studies of the gated currents in the photoreceptors which are initiated following changes in photocurrent, which shape and process the light response of the photoreceptors. Both rods and cones have an inward gated current that is activated by membrane hyperpolarization. Photoreceptors are also electrically coupled, and the gated current in each membrane coupled mosaic serves to enhance temporal and spatial resolution. We have also begun to look at the effects of synaptic transmission from horizontal cells to cones - the pathway responsible for the first level of lateral interactions in vision. Synaptic transmitter here seems to increase conductance to ions with an equivalent potential near -70 mV. Our proposed work will elucidate the membrane and pharmacological properties of this feedback synapse, as well as synaptic transmission from the photoreceptors to the second order cells.